[英]HttpLisenter Start method fails on windows service start
我一直在鬼混HttpListenter的資料,網址為:
http://msdn.microsoft.com/en-us/library/system.net.httplistener.aspx
它可以在標准控制台應用程序上很好地工作,但是我正在嘗試使其作為Windows服務工作。 應用程序日志顯示,服務啟動時,它將在HttpListener.Start()方法上失敗。 我很困惑為什么會發生這種情況。
這是課程(這里是概念質量的證明:)
public class Server
{
public Server()
{
var thread = new Thread((Start));
thread.Start();
}
public static void Start()
{
while(Listen())
{
}
}
private static bool Listen()
{
var prefixes = new[] {"http://192.168.0.7/"};
if (!HttpListener.IsSupported)
{
Console.WriteLine ("Windows XP SP2 or Server 2003 is required to use the HttpListener class.");
return false;
}
// URI prefixes are required,
// for example "http://contoso.com:8080/index/".
if (prefixes == null || prefixes.Length == 0)
throw new ArgumentException("prefixes");
// Create a listener.
HttpListener listener = new HttpListener();
// Add the prefixes.
foreach (string s in prefixes)
{
listener.Prefixes.Add(s);
}
listener.Start(); //THIS FAILS IN WINDOWS SERVICE AS LOCAL SYSTEM
//Console.WriteLine("Listening...");
//// Note: The GetContext method blocks while waiting for a request.
//HttpListenerContext context = listener.GetContext();
//HttpListenerRequest request = context.Request;
//// Obtain a response object.
//HttpListenerResponse response = context.Response;
//// Construct a response.
//string responseString = "<HTML><BODY> " + DateTime.Now + "</BODY></HTML>";
//byte[] buffer = System.Text.Encoding.UTF8.GetBytes(responseString);
//// Get a response stream and write the response to it.
//response.ContentLength64 = buffer.Length;
//System.IO.Stream output = response.OutputStream;
//output.Write(buffer,0,buffer.Length);
//// You must close the output stream.
//output.Close();
//listener.Stop();
return true;
}
}
相關日志:錯誤:
Application: Stout.Workers.Service.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.Net.HttpListenerException
Stack:
at System.Net.HttpListener.Start()
at Stout.Workers.Service.Server.Listen()
at Stout.Workers.Service.Server.Start()
at System.Threading.ThreadHelper.ThreadStart_Context(System.Object)
at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
at System.Threading.ThreadHelper.ThreadStart()
錯誤:
Faulting application name: Stout.Workers.Service.exe, version: 0.0.0.0, time stamp: 0x50d0cd99
Faulting module name: KERNELBASE.dll, version: 6.2.9200.16451, time stamp: 0x50988950
Exception code: 0xe0434352
Fault offset: 0x00014b32
Faulting process id: 0x1e70
Faulting application start time: 0x01cddd5bb3e8500b
Faulting application path: C:\Users\Chad\Dropbox\Personal\Projects\Stout\Stout\Workers\Service\bin\Debug\Stout.Workers.Service.exe
Faulting module path: C:\Windows\SYSTEM32\KERNELBASE.dll
Report Id: f1aa9986-494e-11e2-be9b-685d43b0551c
Faulting package full name:
Faulting package-relative application ID:
信息:
Fault bucket , type 0
Event Name: CLR20r3
Response: Not available
Cab Id: 0
Problem signature:
P1: stout.workers.service.exe
P2: 0.0.0.0
P3: 50d0cd99
P4: System
P5: 4.0.30319.18016
P6: 505702c9
P7: 206c
P8: 5c
P9: System.Net.HttpListenerException
P10:
我猜您正在嘗試在偵聽器上接受多個請求。 如果仔細閱讀代碼,您會發現您正在實例化無限數量的偵聽器,而不是創建一個偵聽器來處理多個調用。
您實際上得到的異常是StackOverflowException(唯一的try-catch
塊無法try-catch
異常),無論您做什么,應用程序都會中斷。
刪除while
循環(只需調用一次Listen),然后在Listen方法中嘗試使用以下方法。
HttpListener listener = new HttpListener();
//add your prefixes here
listener.Start();
AsyncCallback processRequest = delegate(IAsyncResult result)
{
//set the listener to listen for next request
listener.BeginGetContext(processRequest, listener);
HttpListenerContext context = listener.EndGetContext(result);
//Your code to handle the request here
}
listener.BeginGetContext(processRequest, listener);
這將使用單個HttpListener
創建您要查找的循環
希望這可以幫助
UPDATE :如果取消注釋請求處理代碼,您將注意到不會發生異常,因為在調用listener.GetContext()
時阻塞了線程,並且偵聽器將掛起,直到接收到請求並且Listen方法不會返回為止。 通過只調用將間接返回的listener.Start()
然后返回true,您就以非常快的速度循環創建了許多監聽器。
您的代碼可能以這種方式工作,但是效率很低,因為您必須為每個請求創建一個偵聽器。 最好讓一個偵聽器異步處理所有請求,因為如果您的一個請求花費10秒執行循環,則在您響應發出請求的客戶端之前,不會創建另一個偵聽器。
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.